The M-51 is an intercontinental-range, solid propellant, MIRV-capable, submarine-launched ballistic missile, that is currently operational in France. Originally, France had planned to replace the M-45 with the M-5, but in 1996 the Ministry of Defense decided the cost of the program was not justified and reduced its capabilities. 1 The M-51 was subsequently developed, and deployed in 2010. The M-51 is the sixth missile in France’s MSBS (Mer-Sol-Balistique-Stratégique) family, following the M-1, M-2, M-20, M-4, and M-45.

The M-51 has considerably greater range than its predecessor, the M-45, as well as improved accuracy and performance capabilities – including penetration aids capable of matching the abilities of the Russian anti-ballistic missile system. 2 Its warheads may also offer an EMP option. 3 These expectations have led some to speculate that French nuclear strategy is broadening from a policy of deterrence to one that includes the possibility of a first-strike; other commentators maintain that the M-51 will simply follow the established French doctrine of deterrence and has only been designed for use against large strategic targets.

The M-51 is believed to be 13.0 m long, 2.35 m in diameter, and 50,000 kg. The estimated range of the missile is 8,000 km. The M-51 will carry between four and six MIRVs using the TN-75 warheads developed for the M-45 missile. Each RV has a total weight of 230 kg while holding a 115 kg warhead. Each MIRV has a yield of 150 kT. 4 The M-51 entered development in 1998, with the first flight in 2004. Subsequent flights tests were made in November 2006, June 2007, January 2010, and July 2010. France began replacing the M-45 with the M-51 in 2010. The first batch of missiles was deployed on Le Terrible, the last of four SNLE-NG (Sous-Marins Nucléaires Lanceurs Engins-Nouvelle Génération) new generation submarines. Eventually, all four SNLE-NG submarines, Le Triomphant, Le Temeraire, Le Vigilant, and Le Terrible, could carry 16 M-51 missiles each.